The invention relates generally to a copier or printer, especially a photographic copier or printer.
More particularly, the invention relates to a photographic roll copier having a platen for a master, e.g., a negative, to be reproduced and a platen for the roll copy material. A projection device produces images of the master on the copy material at different magnifications. The projection device contains several projection units which can be selectively moved into the optical path between the platens, and each projection unit includes one or more objectives.
In the copying art, it is necessary to bring projection units of varying focal length into the path of the copy light in order to produce multiple images, i.e., so-called packages.
The German patent 26 14 090 describes a lens holder for a photographic copier. The projection units are mounted on separate platforms which are shiftable perpendicular to the optical axes of, and relative to, the objectives in order to position the latter. The platforms may be driven pneumatically, for example.
The German Offenlegungsschrift 28 49 725 discloses a device for the production of photographic documents and of images in various formats. The device consists of a carrier which holds a plurality of projection units having different focal lengths, and the carrier is movable perpendicular to the optical axes of the objectives and transverse to the platens for the masters and copy material. The projection units are positioned on the carrier in order of magnification. Accordingly, in order to permit production of the largest and smallest formats, the length of the carrier, as considered along a direction parallel to the optical axis, is at least equal to the maximum possible master platen-objective spacing minus the minimum possible spacing.
Also known are arrangements in which the projection units are mounted on a rotatable carrier. See, for instance, U.S. Pat. No. 3,169,441.
A brochure of Castle Rock Manufacturing, Inc. describes a package printer which can be either microprocessor-controlled or computer-controlled. Film sizes of 35 mm to 70 mm can be exposed by rapid, simultaneous exchange of rotary lens platens. This device makes it possible to produce single formats as well as packages with little waste of paper and, by virtue of an integrated cutter, with little work. Exposure takes place with white light or by means of an automatic, integrated, color exposure control unit.
In all prior art arrangements, the use of several magnifications necessarily results in bulkiness of the projection units and of the individual components which carry the objectives. The accompanying large masses have an adverse effect, particularly as regards positioning and objective exchange time. When pneumatic drives are employed, jerky loading of components, adjustment problems and noisy positioning can be expected.